Noise radiated by an electrical automotive powertrain

Aachen Acoustics Colloquium – AAC, Aachen (Germany), November 2013

The automotive industry has entered a phase of change. Hybrid and electric vehicles are emerging and with them the need to include these new technologies in the design process, especially in numerical simulation methods.

The noise radiated by an electrical motor is very different from that radiated by a combustion engine. It is characterized by the emergence of high frequency pure tones that can be annoying, even if the overall noise level is lower than that of a combustion engine. To evaluate sound perception of future users during the design phase, it is necessary to simulate the noise radiated by the electrical machine and listen it.

In a first step, this paper describes a complete approach to simulate the noise radiated by electric motors. The principle of this multiphysical method is first to calculate the excitation due to electromagnetic phenomena using an electromagnetic finite element solver. This excitation is then projected onto the structure mesh of the stator in order to calculate the dynamic response. Finally, radiated sound power is calculated with the aid of a finite element method. The calculation methodology assumes a weak coupling between the different physical levels.

In a second step, the paper focuses on the experimental validation: this 3-step procedure is applied to an automotive electric motor and the calculation is performed for an engine run-up. Comparison between measurements and calculation are presented.